Green Roofs As Urban Ecosystems: Ecological Structures, Functions And Services

Erika Oberndorfer, Brad Bass - Environment Canada, Jeremy T. Lundholm - Saint Mary's University, Reid Coffman - Kent State University, Hitesh Doshi, Stuart Gaffin - Columbia University, Karen K.Y Liu, Nigel Dunnett - The University of Sheffield, Manfred Köhler - Hochschule Neubrandenburg, D. Bradley Rowe - Michigan State University

Green roofs (roofs with a vegetated surface and substrate) provide ecosystem services in urban areas, including improved storm-water management, better regulation of building temperatures, reduced urban heat-island effects, and increased urban wildlife habitat. This article reviews the evidence for these benefits and examines the biotic and abiotic components that contribute to overall ecosystem services. We emphasize the potential for improving green-roof function by understanding the interactions between its ecosystem elements, especially the relationships among growing media, soil biota, and vegetation, and the interactions between community structure and ecosystem functioning. Further research into green-roof technology should assess the efficacy of green roofs compared to other technologies with similar ends, and ultimately focus on estimates of aggregate benefits at landscape scales and on more holistic cost-benefit analyses.